ATLANTA - A Fulton County judge stopped Monday's scheduled execution of Warren Lee Hill to consider a legal challenge to a state law prohibiting the release of information on Georgia's supply of lethal injection drugs.

Superior Court Judge Gail S. Tusan issued a temporary stay until a hearing could be held Thursday morning, said Hill's attorney Brian Kammer. The execution could be rescheduled for as soon as Thursday evening if the judge decides to lift the stay.

"Today, the court found that more time is needed to explore Mr. Hill's complaint, which raises serious concerns about the extreme secrecy surrounding the execution process in Georgia," Kammer said in a statement. "There is far too much we do not know about how the state intends to proceed in this, the most extreme act a government can take against a citizen."

The lawsuit filed Friday focuses on a state law that recently took effect, which prohibits the release of identifying information about any person or company participating in an execution. Supporters of the law have said it's necessary to protect participants from retaliation and could help the state obtain drugs from companies or pharmacies that might not want people to know they are involved in executions.

Nationally, it has become increasingly difficult for states to obtain a lethal injection drug because the manufacturer has said it doesn't want it used in executions.

Monday was not the first time Hill's scheduled execution has been delayed pending a challenge to the state's lethal injection procedure.

Last July, Hill's planned execution was put on hold as his attorneys challenged a plan by the state to change from a three-drug process to a single lethal dose of pentobarbital. The state previously used pentobarbital to sedate inmates before injecting pancuronium bromide to paralyze them and then potassium chloride to stop their hearts. The Georgia Supreme Court later sided with the state and cleared the way for the execution.

But then the state's supply of the drug expired in March. The Department of Corrections used a compounding pharmacy to obtain pentobarbital for Hill's scheduled execution, according to documents obtained by The Associated Press under a records request. The name of the pharmacy was not released, nor was the name of the physician who wrote the prescription for the drug.

Compounding pharmacies custom-mix small batches of a drug for specific clients. They've come under scrutiny after a deadly meningitis outbreak was linked to contaminated injections from a Massachusetts compounding pharmacy. The FDA considers compounding pharmacy products unapproved drugs and does not verify their safety or effectiveness.

In the lawsuit, Hill's attorneys argued they have been unable to determine whether the drugs were obtained from a legitimate source and are not "counterfeit, expired or tainted in some way likely to cause him grave harm or suffering during his execution."

In its response, the state Attorney General's Office argued the state law is constitutional and provided an affidavit from an independent lab verifying the drug had been analyzed and was safe to use.

Hill, 53, was sentenced to death in the 1990 killing of fellow inmate Joseph Handspike. At the time, Hill was serving a life sentence for the 1986 killing of his girlfriend, Myra Wright.

Separately, Hill's planned execution has prompted criticism from disability advocates who have joined forces with the NAACP and Amnesty International to protest. Hill's attorneys have long argued he is mentally disabled and point to three doctors who originally examined Hill for the state who now say they believe he is mentally disabled.

Attorneys for the state have argued Hill has failed to prove he's mentally disabled and that his case has been thoroughly reviewed by several courts. The U.S. Supreme Court is scheduled to consider the case on Sept. 30 but Hill's attorneys have been appealing for them to intervene sooner.